Outdoor barbecue grills have become very popular for outdoor cooking and are particularly enjoyed at both family cookouts as well as casual outdoor social occasions. As is well known to one skilled in the art, barbecue grills utilize different types of heating means for cooking meats and other foods. A conventional and well-known type of barbecue grill such as the WEBER.RTM. brand kettle grill utilizes combustible charcoal briquettes (or wood chips and/or wood pellets) which must be replenished with each use of the grill for cooking. More recently barbecue grills have become popular which utilize propane (or natural gas) and electric heating elements, and these types of grills have displaced many conventional grills utilizing combustible charcoal briquettes due to their greater convenience to the user.
The propane (or natural gas) and electric barbecue grills act to heat permanent cement briquettes or lava rock so that greases from the food being cooked will fall thereon and be vaporized in order to create a smokey environment for the food being cooked and to impart additional smokey aroma and flavor thereto similar to the flavor imparted to food being cooked with conventional combustible briquettes on a barbecue grill. Thus, the propane (or natural gas) and electrically heated barbecue grills provide a measure of convenience which is not obtainable with conventional combustible briquette-heated barbecue grills. Yet, the more convenient and popular propane (or natural gas) and electrically heated barbecue grills provide substantially the same measure of tasty, smokey flavor which outdoor cooks obtain from old-fashioned, conventional barbecue grills.
Regardless of the type of barbecue grill utilized for outdoor cooking, it is well known that it is most difficult to obtain any measure of control over the heat in the bottom of the grill versus the heat in the top of the grill. The ability to control the heat in the bottom of the grill relative to the heat in the top of the barbecue grill would be a very desirable feature of a grill since foods being cooked segregate very distinctly into two classes: (1) foods such as steak, hamburger, hot dogs and other hot grill items which primarily are cooked with heat from below (or the lower portion of the grill); and (2) foods such as roast, turkey, prime rib, leg of lamb, pies, and casseroles which are most suitably cooked by uniform heat from both above and below (the lower and upper portions of the grill).
In the past, it has been very difficult to cook the latter types of foods on an outdoor grill, and thus these types of foods have more traditionally been cooked in conventional electric or gas indoor kitchen ovens. However, some success has been achieved to date in developing a barbecue-type outdoor grill which can cook both types of foods. A commercially successful example of such an outdoor grill is the HOLLAND.RTM. brand grill manufactured by The Holland Company of the Carolinas located in Apex, N.C. This grill is the subject matter of applicant's own U.S. Pat. No. 4,773,319 which issued on Sep. 27, 1988. However, although capable of successfully cooking both types of foods, the HOLLAND.RTM. brand grill does not provide a high degree of selective control of the relative heat in both the lower and upper portions of the grill, but rather provides a relatively uniform heat within the entire grill. The grill thus very effectively cooks foods requiring uniform heat distribution but less efficiently cooks foods primarily requiring heat from therebeneath in order to be most effectively cooked.
The quest therefore continues for the development of a barbecue grill which enables the user to control the relative heat distribution between the bottom and top of the enclosed grill so as to optimize the cooking of foods which require uniform heat distribution (e.g., roast and turkey) as well as foods requiring primarily heat from below (e.g., hamburgers, hot dogs and other hot grill items).